1. Field of the Invention
The present invention relates to a composite adsorbent which effectively removes various offensive odors of amines, aldehydes, sulfides, etc. originating for industrial and automotive exhaust gas, and other smells of tobacco, human body, human waste, foods, etc. encountered in daily life.
2. Description of the Related Art
Human activities in living rooms, offices, kitchens, automobiles, etc. accompany various offensive odors. It is said that offensive odors in a car contain thousands of components originating from cigarette smoke, sweat, exhaust gas, dust, etc. The Offensive Odor Control Law (Japanese law) describes the following twelve components as important, namely, ammonia, methyl mercaptan, hydrogen sulfide, methyl sulfide, methyl disulfide, trimethylamine, acetaldehyde, styrene, n-butyric acid, n-, iso-valeric acid, and propionic acid.
The conventional methods of removing such offensive odors are by masking with an aromatic or by adsorption with activated carbon or silica gel. However, these methods have disadvantages. Masking with an aromatic does not remove the components of offensive odors in itself, and there may be an instance where the aromatic itself smells unpleasant. As to activated carbon and silica gel, they limit their adsorbate. For example, activated carbon is not effective at all for odors originating from such basic substances as ammonia and trimethylamine.
Another method is chemical removing. It removes offensive odors by the chemical reaction like an acid-base neutralization reaction. It permits the sure removal of both acid odors of acetaldehyde, hydrogen sulfide, etc. and basic odors of ammonia, trimethylamine, etc. More precisely, acid odors and basic odors are removed by neutralization with a basic adsorbent and an acid adsorbent, respectively. However, this chemical adsorbent has also a disadvantage that the basic adsorbent and the acid adsorbent react with each other and become deactivated when they are supported on the same carrier or dispersed in the same liquid simultaneously. This makes it necessary to use separate carriers for the basic and acid adsorbents. As the result, the net amount of each ingredient that can be supported on carriers is reduced and hence the resulting composite adsorbent decreases in deodorizing capacity.